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| author |   Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> | 2017-03-22 16:27:49 -0300 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2017-03-28 10:52:00 +1100 |
| commit | 3b5bf42b81d56085fd58692b5117f69aa77fdff7 (patch) | |
| tree | 0af0955fad922cd8a531a55bc8c261b072a369f4 /arch/powerpc/xmon | |
| parent | powerpc/64s: POWER8 add missing machine check definitions (diff) | |
| download | linux-dev-3b5bf42b81d56085fd58692b5117f69aa77fdff7.tar.xz linux-dev-3b5bf42b81d56085fd58692b5117f69aa77fdff7.zip | |
powerpc/xmon: Fix an unexpected xmon on/off state change
Once xmon is triggered by sysrq-x, it is enabled always afterwards even
if it is disabled during boot. This will cause a system reset interrupt
fail to dump. So keep xmon in its original state after exit.
We have several ways to set xmon on or off.
1) by a build config CONFIG_XMON_DEFAULT.
2) by a boot cmdline with xmon or xmon=early or xmon=on to enable xmon
and xmon=off to disable xmon. This value will override that in step 1.
3) by a debugfs interface, as proposed in this patchset.
And this value can override those in step 1 and 2.
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/xmon')
| -rw-r--r-- | arch/powerpc/xmon/xmon.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 16321ad9e70c..a89db1b3f66d 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -76,6 +76,7 @@ static int xmon_gate; #endif /* CONFIG_SMP */ static unsigned long in_xmon __read_mostly = 0; +static int xmon_on = IS_ENABLED(CONFIG_XMON_DEFAULT); static unsigned long adrs; static int size = 1; @@ -3302,6 +3303,8 @@ static void sysrq_handle_xmon(int key) /* ensure xmon is enabled */ xmon_init(1); debugger(get_irq_regs()); + if (!xmon_on) + xmon_init(0); } static struct sysrq_key_op sysrq_xmon_op = { @@ -3318,7 +3321,7 @@ static int __init setup_xmon_sysrq(void) __initcall(setup_xmon_sysrq); #endif /* CONFIG_MAGIC_SYSRQ */ -static int __initdata xmon_early, xmon_off; +static int __initdata xmon_early; static int __init early_parse_xmon(char *p) { @@ -3326,10 +3329,12 @@ static int __init early_parse_xmon(char *p) /* just "xmon" is equivalent to "xmon=early" */ xmon_init(1); xmon_early = 1; - } else if (strncmp(p, "on", 2) == 0) + xmon_on = 1; + } else if (strncmp(p, "on", 2) == 0) { xmon_init(1); - else if (strncmp(p, "off", 3) == 0) - xmon_off = 1; + xmon_on = 1; + } else if (strncmp(p, "off", 3) == 0) + xmon_on = 0; else if (strncmp(p, "nobt", 4) == 0) xmon_no_auto_backtrace = 1; else @@ -3341,10 +3346,8 @@ early_param("xmon", early_parse_xmon); void __init xmon_setup(void) { -#ifdef CONFIG_XMON_DEFAULT - if (!xmon_off) + if (xmon_on) xmon_init(1); -#endif if (xmon_early) debugger(NULL); } |